Double Vision Facts
Double vision is among the most disorienting and devastating vision disorders. People suffering from double vision will often times go to great lengths to alleviate the double image, such as wearing a patch or covering an eye. This eliminates the vision from one eye, alleviating their double vision.
Double vision is caused when the two eyes do not align and work together. The overall encompassing term for this is strabismus. There are many forms of strabismus, many causes and some effective treatments.
Exotropia refers to strabismus when an eye turns outward and esotropia is when an eye crosses. Hypertropia is when an eye turns up and hypotropia when an eye turns down. The strabismus can be constant or intermittent and can occur in combinations such as hyper-esotropia, or hypo-exotropia.
If strabismus occurs from birth or in early childhood there usually will not be associated double vision. The child’s brain is very adaptable and will learn how to turn off, or ignore the mis-aligned part of vision from the eye that turns. This is called suppression.
If strabismus occurs after childhood, then there usually is an underlying cause. This type of strabismus that occurs after the eyes had previously been aligned is called acquired strabismus. Some of the more common causes of acquired strabismus are head injury, stroke, multiple sclerosis, aneurysm, hemorrhage, diabetes, brain tumor and hypertension. In acquired strabismus, there is nearly always double vision.
In the past there were few options to offer people with acquired strabismus and double vision. They were frequently told to cover or patch an eye. While this is effective in eliminating the double vision, there is a high price to pay. Patching an eye causes the loss of depth perception and the loss of between 25 and 30 percent of peripheral vision.
Fortunately there are now effective solutions for double vision thanks to the work and research done by Dr. Politzer and his colleagues around the country.
The “Spot Patch”, developed by Dr. Politzer, is a method of partial and selective occlusion of just the small portion of vision that causes double vision. It does not eliminate depth perception and does not limit peripheral vision at all.
Prisms are ophthalmic devices to reorient the direction of light. They can be manufactured into prescription lenses, or be temporarily mounted to existing lenses. Prisms can often times be used to help offset some of the mis-alignment of the eyes and allow single vision.
Vision rehabilitation therapy is a program of exercises to help strengthen and coordinate the eyes to regain single vision. It is analogous to physical therapy for the eyes. Vision rehabilitation is typically done in conjunction with the “Spot Patch”, prism, or both.
Strabismus, ophthalmoplegia, gaze palsy, and decompensated binocular skills are some of the visual sequelae to head injury, stroke and other neurologically compromising conditions. If the patient does not have and organic loss of vision, or does not suppress, diplopia ensues. Vision therapy and/or prisms and lenses can sometimes help the patient achieve fusion and alleviate the diplopia. When these are not successful and fusion cannot be achieved, intractable diplopia results.
Various methods have been tried to eliminate diplopia. These include constant patching, alternate patching, and a fogging lens. Although these are all effective methods to eliminate the diplopia, there are side effects. They seriously impair peripheral vision and peripheral fusion which in turn impairs orientation, mobility, balance and peripheral field of view. A new method that does not have these limitations has been successfully evaluated.
The “spot patch” is a method to eliminate intractable diplopia without compromising peripheral vision. It is a round patch made of Transpore tape, 3-M blurring film (or another such translucent tape). A mirror coating, or tint can be placed on the lens to improve cosmesis and reduce other people’s ability to see the spot patch. The spot patch is placed on the patient’s glasses and directly in the line of sight contributing to the diplopia.
The diameter is generally about one centimeter, but will vary on the individual angular subtense required for the particular strabismus, or gaze palsy. Final size and placement is determined by evaluating different sizes and shapes to arrive at the smallest one, which effectively eliminates the diplopia. If the patient is a constant unilateral strabismic, or has a unilateral gaze palsy, then the spot patch can be placed before that eye. Otherwise, an alternate spot patch is indicated.
This method has now been used on hundreds of patients with resounding success. It has allowed these people improved balance, mobility, field of vision, and, certainly not least of all, better cosmesis. Given these advantages, the spot patch should become a first option of choice for patients with intractable diplopia